Toxicity of herbicides on biological parameters of Trichogrammatidae
摘要
Maize plant productivity is reduced by weeds and defoliating caterpillars. The weed management in maize crops in Brazil is mainly accomplished with nicosulfuron- and atrazine-based herbicides, and of lepidopteran pests with the releases of species of Trichogrammatidae. The objective was to evaluate the female parasitism and emergence rates and sex ratio (%) of 10 Trichogrammatidae species, in a free-choice test, submitted to a mixture of the herbicides Sanson 40 SC® (a.i. nicosulfuron; dose: 30 g ha–1) + Gesaprim 500 Ciba-Geigy® (a.i. atrazine; dose: 1500 g ha–1) in the laboratory. The herbicide mixture minimally influenced the biological parameters, including parasitism and emergence rates, as well as sex ratio, of Trichogramma pretiosum, followed by Trichogramma bennetti, Trichogrammatoidea annulata and Trichogramma brasiliensis. The other species of the Trichogrammatidae family showed susceptibility, probably due to increased female mortality or inhibition of oviposition.